The present invention relates to prostaglandin analogs, and process for the preparation thereof, as precursors for the synthesis of oligomeric mixtures showing biological activity with regard to the protection of oxidative phosphorylation in degenerated mitochondria. More particularly, the invention relates to such ethyl analogs and related compounds having low molecular weights and abbreviated side chains which make derived oligomers more amenable to structural elucidation by conventional techniques.
A new class of polymeric derivatives designated PGB.sub.x and the syntheses thereof are disclosed in U.S. Pat. No. 4,153,808 issued May 8, 1979 to B. David Polis et al., and U.S. Pat. No. 4,245,111 issued Jan. 13, 1981 to B. David Polis et al., which have the unique property of restoring the in vitro phosphorylating ability of degraded mitochondria. The precursors used in the syntheses are prostaglandins such as PGB.sub.1, 13-14-dehydro-PGB.sub.1 and 15-keto-PGB.sub.1 methyl ester, each having a relatively complex molecular structure resulting in oligomeric derivatives which are not amenable to structural elucidation by conventional spectroscopic techniques necessary for defining the structure-activity relationships.
One well-known method of structural elucidation of the reaction products is by assignment of the carbon-13 chemical shifts. Unequivocal assignments are required in order that the precursors may serve as models for the components having the desired mitochondrial activity. However, the chemical shift assignments for the prior art precursors are based solely on analogy to other classes of prostaglandins not having disubstituted cyclopentenone systems. Thus, several assignments associated with the systems of PGB.sub.x were uncertain.
In addition, the prior methods of preparing the prostaglandin precursors of the oligomeric mixture PGB.sub.x are relatively inefficient and indirect, resulting in longer reaction times and higher costs.